+
−/*
+
−********************************************************************************
+
−*
+
−*      GSM AMR-NB speech codec   R98   Version 7.6.0   December 12, 2001
+
−*                                R99   Version 3.3.0                
+
−*                                REL-4 Version 4.1.0                
+
−*
+
−********************************************************************************
+
−*
+
−*      File             : d4_17pf.c
+
−*      Purpose          : Algebraic codebook decoder
+
−*
+
−********************************************************************************
+
−*/
+
−
+
−/*
+
−********************************************************************************
+
−*                         MODULE INCLUDE FILE AND VERSION ID
+
−********************************************************************************
+
−*/
+
−#include "namespace.h"
+
−#include "d4_17pf.h"
+
− 
+
−/*
+
−********************************************************************************
+
−*                         INCLUDE FILES
+
−********************************************************************************
+
−*/
+
−#include "typedef.h"
+
−#include "basic_op.h"
+
−#include "no_count.h"
+
−#include "cnst.h"
+
−#include "graytab.h"
+
−
+
−/*
+
−********************************************************************************
+
−*                         LOCAL VARIABLES AND TABLES
+
−********************************************************************************
+
−*/
+
−#define NB_PULSE 4
+
− 
+
−/*
+
−********************************************************************************
+
−*                         PUBLIC PROGRAM CODE
+
−********************************************************************************
+
−*/
+
−/*************************************************************************
+
− *
+
− *  FUNCTION:  decod_ACELP()
+
− *
+
− *  PURPOSE:   Algebraic codebook decoder
+
− *
+
− *************************************************************************/
+
−
+
−void decode_4i40_17bits(
+
−    Word16 sign,   /* i : signs of 4 pulses.                       */
+
−    Word16 index,  /* i : Positions of the 4 pulses.               */
+
−    Word16 cod[]   /* o : algebraic (fixed) codebook excitation    */
+
−)
+
−{
+
−    Word16 i, j;
+
−    Word16 pos[NB_PULSE];
+
−
+
−    /* Decode the positions */
+
−
+
−    i = index & 7;                                       logic16 ();
+
−    i = dgray[i];                                        move16 ();
+
−
+
−    pos[0] = add(i, shl(i, 2));   /* pos0 =i*5 */        move16 ();
+
−
+
−    index = shr(index, 3);
+
−    i = index & 7;                                       logic16 ();
+
−    i = dgray[i];                                        move16 ();
+
−
+
−    i = add(i, shl(i, 2));        /* pos1 =i*5+1 */
+
−    pos[1] = add(i, 1);                                  move16 ();
+
−
+
−    index = shr(index, 3);
+
−    i = index & 7;                                       logic16 ();
+
−    i = dgray[i];                                        move16 ();
+
−
+
−    i = add(i, shl(i, 2));        /* pos2 =i*5+1 */
+
−    pos[2] = add(i, 2);                                  move16 ();
+
−
+
−    index = shr(index, 3);
+
−    j = index & 1;                                       logic16 ();
+
−    index = shr(index, 1);
+
−    i = index & 7;                                       logic16 ();
+
−    i = dgray[i];                                        move16 ();
+
−
+
−    i = add(i, shl(i, 2));        /* pos3 =i*5+3+j */
+
−    i = add(i, 3);
+
−    pos[3] = add(i, j);                                  move16 ();
+
−
+
−    /* decode the signs  and build the codeword */
+
−
+
−    for (i = 0; i < L_SUBFR; i++) {
+
−        cod[i] = 0;                                      move16 ();
+
−    }
+
−
+
−    for (j = 0; j < NB_PULSE; j++) {
+
−        i = sign & 1;                                    logic16 ();
+
−        sign = shr(sign, 1);
+
−
+
−        test ();
+
−        if (i != 0) {
+
−            cod[pos[j]] = 8191;                          move16 ();
+
−        } else {
+
−            cod[pos[j]] = -8192;                         move16 ();
+
−        }
+
−    }
+
−
+
−    return;
+
−}